The composition of this radiation can vary depending on what may be ionized. Visible light, near ultraviolet, infrared, microwave and radio waves are all examples of non-ionizing radiation, though visible and near ultraviolet can also ionize some molecules. The light from the Sun that reaches the earth is largely composed of non-ionizing radiation, with the notable exception of some ultraviolet rays. However, most ionizing radiation is filtered out by the atmosphere.

Because it is lower energy radiation, the use of this type of radiation in medical fields and everyday life poses fewer health risks than ionizing radiation in forms such as X-rays.